The themes of territorial rebalancing and the development of the most disadvantaged territories represent increasingly central issues in the territorial planning actions and strategies promoted at a European level. Within this framework of growing interest is also the Agenda 2030, which aims to raise awareness of the urgency of addressing the issue of marginal areas at risk of abandonment, and identifying measures to counter it. The problem of housing erosion is complex and multifaceted because it is often interrelated with a range of phenomena, with controversial urban dynamics. Our research intends to contribute to the issue of marginal territories by offering a more structured analysis of the phenomena taking place at the scale of historical centres, which allows us to reflect on the repercussions in terms of the conservation of the built heritage. The investigation methodology makes use of a case study identified in the context of inner areas in Italy: Leonforte, a small town located in the hinterland of Sicily, has a historic centre in a declining condition. Its current condition of partial abandonment entails the coexistence of phenomena of disuse and transformation: this situation, which can also be observed in other contexts in the process of abandonment, can be seen as a contradiction of the centres in the internal areas that further complicates the prospects for intervention. To support the development of suitable actions and strategies, the study aims to explore the degree of transformation and loss of integrity of the built environment through the evaluation of an aggregate index based on the Multi-attribute Value Theory (MAVT). Analysis of the aggregate index of transformation and loss of integrity building (TLI index) based on its quartiles using QGIS highlights the characteristics of permanence and the historical-architectural qualities of the built environment. The recognition of these residual values remains central in the elaboration of future intervention choices to be implemented in the difficult context of a centre undergoing abandonment.